This invention relates, in general, to a method of removing contaminants, including, but not limited to, a method of cleaning contaminants from a semiconductor material.
Many methods are used to remove contaminants from a semiconductor material. In the past, one method involved exposing a semiconductor material to an anhydrous cleaning gas mixture containing one part by volume of nitric oxide and one part by volume of hydrogen chloride with a carrier gas of at least four parts molecular nitrogen at a temperature range of 850.degree. to 1100.degree. C. for a period of less than 10 minutes.
Another cleaning method entails exposing a semiconductor material to a temperature of 900.degree. to 1300.degree. C. in an ambient which includes hydrogen chloride and about 0.5 to 1% oxygen by volume to grow a protective silicon dioxide film on the surface of the semiconductor material to a thickness of not more than about 150 Angstroms for a period of 20 to 30 minutes.
Although these processes may remove some contaminants, it is desirable to improve the efficiency of contaminant removal so that a substantial amount of contaminants are removed, because contamination problems can be detrimental to the manufacture of semiconductor devices. Contamination can result in poor reliability and poor electrical performance. In particular, contaminants can cause the formation of gate oxide layers which have low rupture voltages and electrical junctions with high leakage, as well as other failures.